Thermostat.



No. 872,402. PATBNTED DEC. 3, 1907. J. H. BRADY. THERMOSTAT.

APPLICATION FILED MAY I2,4 1906.

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PATENT OFFICE.

JOSEPH H. BRADY, OF KANSAS CITY, MISSOURI.

TI-DERMOSTAT.

Specification of Letters Patent.

Patented Dec. 3, 1907.

Application filed May 12.1906. Serial No. 316.445-

' To all 'whom t may concern:

In practice the instrument is placed inl communication with a tank containing fluid under pressure and the diaphragm-valve of a radiator so that when the temperature exceeds a predetermined degree the thermostat will automatically open communication between the tank and the valve and permit com ressed air or other fluid to flow from the ormer to the latter. The fluid acting upon the valve will close the same and thus cut 0H the steam or other heating agent from the radiator. lVhen the temperature falls below normal the thermostat will automatically close communication between the tank and the valve so that the latter relieved of pressure will automatically open and allow the heating agent to enter the radiator.

The invention consists in the combination of an expansive medium which varies in length according to changes in temperature, a system of levers for compounding the movements derived from said medium, and `a valve 'actuated by the levers for the purpose of controlling the flow of fluid from the tankto the diaphragm-valve.

Referring now to the accompanying drawing which illustrates the invention, Figure 1 represents a front elevation of the thermostat. Fig. 2 shows a side elevation of the same. Fig. 3 is an enlar ed detail, partly in section, taken on lineII of Fig. 2. Fig. 4 is a sectional plan view taken on line IV-IV of In constructing the invention I employ a back-plate 1 provided with ears 2 for the reception of screws or nails whereby the instrument may be reliably secured to the surface `of a wall.

`tion of an expansive medium 5 rigidly held therein by transverse bolts 6. The expansive medium 5 preferably consists of ebonite or other material sensitive to the fluctuations of'temperature so that it will be expanded or contracted by a'lvariation of one or more degrees. As said expansive medium is rigidly iixed at its lower end all movements occasioned by the expansion or contraction thereof will be imparted to its upper terminal and thereby transmitted to a system of levers provided for the purpose of compounding the length of said movements, as will hereinafter appear.

7 designates a metallic cap iixed to the upper terminal of the expansive medium and provided with two threaded holes for the reception of a pair of threaded screws S adjustably arranged therein and provided with jam nuts 9 adapted to engage the upper surface of the cap and thus reliably lock the screws from accidental movement. The upper ends of screws 8 have knife-edges 10 which bear against the underside of a pair of oppositely-disposed levers 11 held from lateral movement upon the knife-edges by loosely embracing flanges 12 extending upwardly from the opposite sides of the screws.

Levers 11 are fulcrumed upon screws 13 and have upper serrated edges 14 for the reception f knife-edges 15 at the lower ends of a pair of links 16. Said links are also provided at their upper ends with knife-edges 17 for engaging the serrated edges 18 of a pair of levers 19 fulcrumed at their outer terminals upon screws 20. Levers 19 have their fulcrumed ends reverselydisposed to the fulcrumed ends of levers 1 1 so that when links 1 6 are adjusted longitudinally thereof the speed and throw of levers 19 will be greatly varied, hence the movement occasioned by the expansion of medium 5 may be greatly increased without employing a multiplicity of levers. Knife-edges 15 and 17 are held from .lateral movement by flanges 21 integral with the ends of the links and loosely embracing the sides of the levers. Flanges 21 have apertures 22 so that the proper ligures on the scales 23 24 on the sides of levers 11, 19, respectively, may be easily read.

Although knifeedges engaging serrations are of course old in this connection, I con sider it important that links having knifeedges at both ends sh all be used with serrated levers whose fulcrums are oppositely disposed, because the independent adjustments of the ends of the links on the two levers variously affect the degree of multiplied ber 28a secured to valve-stem 27 and the` bottom wall of the chamber. Valve-stem 27 is provided at its upper portion with a laterally-extending arm 30 secured thereto by lock-nuts 31.

32 designates a valve-plug iixed to the oppos'ite end of arm 30 and extendingr through guidesV 33 projecting from the rear wall of the chamber. The ends of plug 32 have needlepoints 34 35 adapted toalternately engage seats in an inlet port 36 and an exhaust port 37 respectively. Inlet port 36 extends through a nipple 38 screwed into the underside oi' chamber 28 and provided with an enlarged threaded end 39 for the reception of a coupling 40 whereby a supply-pipe 41 is connected thereto. Pipe 41 leads from a tank, not shown, containin fluid under pressure for actuating the cgliaphragm-valve, not shown.' Exhaust port 37 extends through an externally-threaded nipple 42 projecting through a threaded opening in the upper wall of chamber 28 so that it may be adjusted closer to or farther from needle-point 35 and' thus shorten or lengthen the time required for said needle-point to become seated therein. Needle-point 34 is normally held to its seat by a coil-spring 43 interposed between arm 30 and the upper guide 33. Spring 43 is assisted in holding needle-point 34 to its seat by another coil-spring 44 embracing a stud 45 on a stem 27 and interposed between the upperjam-nut 31 and a'cup 46. Cup 46 is swiveled to the lower endv of a screw 47 adjustably'engagin the internal threads 48 of a boss 49 integra with the upper wall of chamber 28. Said screw is provided with a groove in its upper end for the reception of a screw-driver whereby it may be adjust-ed at will to regulate the pressure of spring 44 upon the valve-stem 27 and the valveplug. Fluid admitted to chamber 28 through port 36 is conducted from said chamber to the diaphragm-valve by a pipe 50.

When setting the thermostat to act at a predetermined degree of temperature reference is made to a thermometer 51 secured to bracket 3.

In practice the levers are adjusted to normally occupy, practically, a horizontal position by screwing screws 8 into cap 7 the proper depth. Then if it is desired to render the instrument very sensitive so that it will be actuated, for instance, by a rise of one degree, one V4or both ends of the links 16`are adjusted closer to the outer terminals of the levers rso that the movement obtained by the expansion of medium 5 will be greatly increased in length and speed and thus actuate the valve-plug 32 accordingly. A liner degree of adjustment is then had by screwing member 42 inwardly so that needle-point 35 will become seated in the lower terminal thereof at the desired time.

The action of the instrument is substantially as follows Wfhen the temperature goes above a predetermined degree the movement caused by the expansion of medium 5 is compounded and transmitted by the levers to valve-stem 27. The latter then, through arm 30, moves the valve-plug upwardly from the inlet port into contact with the exhaust port so that the fluid entering chamber 28 will be conducted by pipe 50 to the diaphragm-valve and close the latter. Said valve is retained in a closed position until the temperature falls to normal. Then as medium 5 contracts it permits springs 43, 44 to force valve-stem 27 downwardly, causing the latter to restore the levers to normal and seat valve-plug 32 in the inlet port. This cuts o the How of fluid t'o chamber 28 and permits that within said chamber and pipe 50 to escape through the exhaust port so that the diaphragm-valve relieved ot' pressure may open and permit the heating agent to enter the radiator.

Having thus described my invention what I claim and desire to secure by Letters-Patent, is A 1. In a device of the character described, the combination with an expansive medium, levers for compounding its movement, a stem moved by the levers, and a spring bearing on the stem; of a chamber, nipples vadjustable through its walls, one of them having an inlet port for the admission of fluid under pressure and the other having' an exhaust port alined with the inlet port, an' outlet pipe for conducting said Huid to the point of use, a single valve plug whose ends are adapted to alternately engage said inletand exhaust, a guide for the plug, an arm connecting the stem and plug, and a second spring on the plug between the guide and arm.

2. In a device of the character described, the combination with an expansive medium, levers for compounding its movement, a stem moved by the levers, and a spring bearing on the stem; of a chamber having an inlet port for the admission of Huid under pressure, an exhaust alined with it, and an outlet pipe for conducting said fluid to the point of use, aA single valve-plug whose ends are adapted to alternately engage said inlet and exhaust, a guide for the plug, an arm connecting tbe stem and plug, and a second spring on the plug between the guide and arm.

3. A thermostat consisting of an expansive medium fixed at one end, a lever moved by the other end of the medium for compounding the movement thereof and having a serrated edge, another lever for compounding the movement of the first-mentioned lever and having a serrated edge, scales on the levers, and a member connecting the levers and having knife-edges adj ustably enagin'g the serrated edges and apertured andges through which said scales may be rea 4. A thermostat consisting of an expansive medium, a lever connected thereto, a second lever arranged vertically above the first-mentioned one and having its fulcrurned end reversely-disposed to the ful- `crumed end of the first lever, a link connecting. said levers and adjustable longitudinally thereon, a valve-stem connected to the second lever,` a chamber into which said' stem extends provided with an internally threaded boss, an inlet port for the admission of fluid under pressure, and an outlet pipe for conducting said fluid to the point of use; a spring bearing against the stem, a cup engaging said spring, a screw swiveled to the cup and adjustably engaging the boss for regulating the tension of the spring, and a va ve-plug carried by the stem for normally closing the inlet port.

5. A thermostat consisting of an expansive medium fixed at one end, a head secured to its other end and having a threaded hole, a screw adjustable therein and having a knife-edge between two flanges, a lever extending across the knife-edge, a second lever above the first and having its fulcrumed end reversely-disposed to the fulcrumed end of the first lever, a link connecting said levers and adjustable at both ends independently thereon, and a stem actuated by the second lever, for the purpose set forth.

6. In a thermostat, the combination with an expansive medium fixed at one end and having a hole at the other, a movable stem, and a system of levers connected with the latter; of a link adj ustably connected at its ends to the levers independently, and a screw threaded into said hole and adjustably connecting one lever with the movable end of said medium, the ends of the link forming -two and the screw a third means of adjustment between the medium and stern.

In testimony whereof I affix my signature, in the presence of two witnesses.

JOSEPH II. BRADY.

Witnesses F. G. FISCHER, J. MOORE. 

